Due to concerns over fuel use, it has become imperative for automotive manufacturers to adopt an ecologic mindset. In this mindset efficiency plays a predominant role when developing new vehicle systems. A new car must waste as little fuel as is practical. Hence it is important to increase the mileage that the car achieves, and so reduce the cost of running the vehicle and its environmental impact.
One particular aspect of fuel usage is vehicle weight. Cost effective means of reducing vehicle weight, without compromising other aspects such as strength, or longevity are desirable, increasingly, aluminium and aluminium alloys are being used to make vehicle body panels and other components of the vehicle.
A problem with all cars is the provision of suitable points at which a vehicle jack can be applied to lift the vehicle, most typically when a wheel is to be replaced. While jacks used in garages are frequently large in terms of the surface area that they occupy, whereby the load on the vehicle is spread over a wide area, such is not the case with on-board jacks that are carried in the car and which vehicle owners use in emergency situations when they need to change a wheel following a tyre puncture. Such jacks need to be email and compact, so that they can be stored in the vehicle in convenient locations without occupying a lot of space, or indeed, themselves representing a substantial load.
Typically, such jacks are provided with a male or female lifting component designed to engage with a corresponding male or female component disposed under the vehicle, in perhaps four locations, one adjacent each wheel around the vehicle, often in or under the side sills of the vehicle. Vehicle sills, like many structural components of a vehicle body, are box structures formed by two or more panels welded together along seams. A frequent arrangement is for the seam itself to form a location for engagement by a jack because the seam is a double layer of the panel material. The panel material itself is almost certainly too weak to support the weight of the vehicle on a small jack head, at least when loaded in a flexing mode of the panel. In a shear mode, however, panels are much stronger and of course sill seams tend to be downwardly directed so that loading the seam tends to be in shear mode anyway. However, even a double layered seam, in shear mode of loading, is most likely still too weak to accept the weight of the entire vehicle on a small jack head. Frequently a third panel piece is connected to the sill wall, perhaps welded between the sill panels in the seam, to reinforce the sill, or rather especially the sill seam, where the jack is intended to engage.
Vehicle sills are inevitably vulnerable to corrosion being located only a few centimeters off the road surface. They are subject to spray from the road in use. Sills are formed during construction of the car body shell up to the eponymous “Body in White” stage of vehicle manufacture, at which stage much of the metal protection systems are applied before assembly of the final car begins. Special coatings and treatments may be applied to such areas as the sills and in many cars sills remain “wet” during life of the vehicle, meaning that they are not sealed and are exposed (internally and externally) to the environment. Consequently, water is frequently entrained within the sills and, especially in winter, salt water from salted roads can commence galvanic corrosion, indeed, this can continue into the summer because, although the sills may be wet, as just described, they do not drain easily and are not flushed out, so that salt can linger. Galvanic corrosion is a particularly aggressive form of corrosion that surface coatings guard against. Even so, stone chips can soon undermine such coatings, so avoiding galvanic corrosion as much as possible is desirable. Galvanic corrosion is caused by employing different metals.
As mentioned above, aluminium is replacing steel as a material of choice. However, aluminium needs to be much thicker than steel to achieve a comparable strength. Aluminium is also not capable of being worked in the same way as steel without compromising strength and, unlike steel, cannot be bent into sharp corners.
One particular form of sill reinforcement for a jacking point in a steel vehicle is a steel box comprising a floor with an aperture, an upstanding back wall and depending side walls that act as reinforcing fillets between the floor and back wall. The back wall and floor are to a side wall and base wall of the sill respectively. A plastic or rubber bung is inserted in the aperture (through a mating aperture of the sill base wall) to provide a jacking point. Such an arrangement is perfectively satisfactory, but it is heavy. Moreover it could not be used in an aluminium-bodied vehicle, especially in a wet zone, without inevitably causing a serious galvanic corrosion problem.
It is an object of the present arrangement to provide a sill reinforcement for the jacking point of a vehicle that does not suffer from, or at least mitigates some of the effects of, the aforementioned issues.